Herschel and JCMT surveys of nearby star-forming regions have provided excellent images of cold dust emission across several wavelengths with unprecedented dynamic range and resolutions. Here we present spectral emissivity index and temperature maps of dust in the star-forming clumps of the Perseus molecular cloud determined from fitting SEDs to the combined Herschel and JCMT observations in the 160 μm, 250 μm, 350 μm, 500 μm, and 850 μm bands, employing the technique developed by Sadavoy et al. (2013). In NGC1333, the most complex and active star-forming clump in Perseus, we demonstrate that CO line contamination in the JCMT SCUBA-2 850 μm band is typically insignificant. The derived spectral emissivity index, β, and dust temperature, T, ranges between 0.8 - 3.0 and 7 - 50 K, respectively. Throughout Perseus, we see indications of heating from B stars and embedded protostars, and smooth β variations on the smaller scales. The distribution of β values seen in each clump differs from one clump to another, and is in general different from the diffuse ISM values (i.e., ~2), suggesting that dust grain evolution is significant in star-forming clumps. We also found coincidences between low β regions and local temperature peaks as well as locations of outflows, which may provide hints to the origins of these low β value grains, and dust grain evolution in star-forming clumps in general. / Graduate / mcychen@uvic.ca

This dissertation presents new Herschel observations at 70 micron, 160 micron, 250 micron, 350 micron, and 500 micron of the Perseus molecular cloud from the Herschel Gould Belt Survey. The Perseus molecular cloud is a nearby star-forming region consisting of seven main star-forming clumps. The Herschel observations are used to characterize and contrast the properties of these clumps, and to study their embedded core populations. First, we probed the exceptionally young clump, B1-E. Using complementary molecular line data, we demonstrate that B1-E is likely fragmenting into a first generation of dense cores in relative isolation. Such a core formation region has never been observed before. Second, we use complementary long wavelength observations at 850 micron to study the dust properties in the larger, more active B1 clump. We find that Herschel data alone cannot constrain well the dust properties of cold dust emission and that long wavelength observations are needed. Additionally, we find evidence of dust grain growth towards the dense cores in B1, where the dust emissivity index, beta, varies from the often assumed value of beta = 2. In the absence of long wavelength observations, however, assuming beta = 2 is preferable over measuring beta with the Herschel-only bands. Finally, we use the source extraction code, getsources, to identify the core populations within each clump from the Herschel data. In addition, we use complementary archival infrared observations to study their populations of young stellar objects (YSOs). We find that the more massive clumps have an excess of older stage YSOs, suggesting that these regions contracted first. Starless cores are typically associated with peaks in the column density, where those found towards regions of higher column density also have higher average densities and colder temperatures. Starless cores associated with a strong, local interstellar radiation field, however, have higher temperatures. We find that the clumps with the most prominent high column density tails also had the highest fractions of early-stage YSOs. This relation suggests that the quantity of high column density material corresponds to recent star formation activity. / Graduate / 0606